1. Field of the Invention
The present invention relates to a method for manufacturing dielectric metal titanate, and especially, to a method by chemical treatment of metal titanium to form metal titanate which is suitable for dielectrics for use in electronic parts.
2. Description of the Prior Art
In accordance with rapid development of various kinds of electronic parts for miniaturizing and making electronic equipments light in weight, particularly a hybrid integrated circuit is strongly requested to be miniaturized, to be light in weight, to have high efficiency and to be used for high frequency, etc. The hybrid integrated circuit consists of a resistor (R), a capacitor (C), an inductance (L), a transistor (Tr) and so on. At present, the capacitor (C) and the inductance (L) are obstacles against miniaturizing and making the hybrid integrated circuit light in weight. If the hybrid integrated circuit can be formed usable for a high frequency, the inductance (L) becomes small but the capacitor (C) is left as a problem unsolved. In the prior art, a solid electrolytic capacitor, a thin film capacitor and so on used in the conventional hybrid integrated circuit are formed by forming a dense and anti-corrosive oxide film on metal such as Al, Ta and the like by anodic oxidation method and effectively using the dielectric property of oxide film made of Al.sub.2 0.sub.3, Ta.sub.2 0.sub.5.
If the dielectric constant of the oxide film is taken as .epsilon., its surface area as S(cm.sup.2) and its thickness as d(cm), capacitance C(.mu.F) is given by the following equation. EQU C=8.855.times.10.sup.-8 .epsilon..multidot.S/d
Accordingly, to make the capacitor small in size, the surface area S and the thickness d have a restriction and so, when it is tried to obtain a large capacitance by the same volume, it is necessary to make the dielectric constant .epsilon. large. The above Al.sub.2 0.sub.3, Ta.sub.2 0.sub.5 are the main materials practically used as oxide film which provides high dielectric constant .epsilon.. As a complex oxide material which has higher dielectric constant .epsilon., there are known, for example, BaTiO.sub.3, SrTi0.sub.3, Ba.sub.1-x Sr.sub.x Ti0.sub.3 which is a complex material thereof. And, it has been tried to form thin films thereof by sputtering. However, according to this method, it is difficult to form a thin film which has a desired composition, thus, this previous method has not yet been put into practice.